A continuous window query is an important class of spatial queries for location-based services. It retrieves spatial objects in a fixed window region of every point on a line segment and indicates the valid segments of them. In this paper, we focus on continuous window queries in wireless data broadcast systems. Since the query result of the continuous window queries has the spatial locality, providing neighbor information of spatial objects can guide clients to efficiently retrieve related objects. Therefore, we propose a neighbor-index method to efficiently support the continuous window queries in wireless data broadcast systems. The proposed method interleaves the neighbor information between spatial objects to guide mobile clients to quickly retrieve the answered objects and save the power consumption of the mobile devices. Experimental results show that our method outperforms the distributed indexing.

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This paper develops a parallel and distributed evolutionary algorithm based on the cloud computing environment and feedback control algorithm to help planners solve the emergency logistic problems. The cloud environment is emulated and used as various virtual machines with different types of evolution procedures. To yield both exploration and exploitation, two crossover processes are deployed on different virtual machines. In the process of crossover, local optimal solutions can be competed and evaluated to form new populations so that the search space can be expanded and the advantaged crossover procedures can be further adopted. The proposed feedback control algorithm based on the evaluation of evolution algorithm can interact and emphasize the process with better performance. According to proposed feedback algorithm, virtual machines with different on demand formatted crossover algorithms can be dynamically established and adopted. Taking the advantage of cloud computing environment and the proposed feedback control algorithm of evolution algorithm, planners can take less effort on deploying both computation power and storage space. Also, it can further applied in various complicated applications more practically.